Clinical Electrophysiology -> Atrial Fibrillation & Atrial Flutter: -> Pharmacology (Antiarrhythmic drugs and anticoagulants) D-PO02 - Poster Session II (ID 47) Poster

D-PO02-230 - Activated Clotting Time Monitoring During Atrial Fibrillation Catheter Ablation: Influence Of Baseline Anticoagulant (ID 267)


Background: Adequate intra procedural anticoagulation is crucial during catheter ablation of atrial fibrillation. While the majority of procedures are now performed with uninterrupted direct oral anticoagulants (DOACs) and intra-procedural administration of unfractionated heparin (UFH) based on activated clotting time (ACT), whether the monitoring strategy recommended for uninterrupted vitamin K antagonist (VKA)-treated patients can be extrapolated to DOAC-treated patients is unknown.
Objective: To study the extent to which ACT may be influenced by various baseline oral anticoagulation strategies
Methods: In 124 patients receiving DOAC (dabigatran, rivaroxaban, apixaban), VKA or no anticoagulant, blood sampling was performed for anticoagulation testing. DOAC concentrations and INR for VKA-treated patients were measured. ACT was determined at baseline, and after spiking with different UFH doses, 0.2, 0.5, 1 and 2 IU/mL.
Results: The extent to which different oral anticoagulants prolonged baseline ACT differed: ACT was longer with dabigatran and shorter with apixaban compared to all other anticoagulants (both p<0.001). The relationship between ACT and the intensity of oral anticoagulation also differed: ACT strongly correlated with INR (r=0.73, p<0.001) and dabigatran concentration (r=0.87, p<0.0001), but not with apixaban or rivaroxaban concentrations. Moreover, dose-response to UFH in terms of ACT prolongation depended on the oral anticoagulant on board, with parallel curves in samples from VKA and dabigatran-treated patients. This contrasted with the FXa inhibitors pattern, especially with apixaban, where ACT prolongation in response to UFH was smaller.
Conclusion: The FXa inhibitors, especially apixaban, appear to influence baseline ACT as well as that in response to UFH, significantly differently from VKAs, while Dabigatran is more similar to VKA. Our findings question the routine extension of currently followed intra procedural anticoagulation strategy, as for VKA, to all DOAC-treated patients.